Device ublkb0 created but not seen by trueno and swap

[goshil]

Hello. Latest EndeavourOS, successfully installed:

cargo install trueno-ublk

Module is loaded:

sudo lsmod |grep ublk
ublk_drv               53248  2

Succesfully created device:

sudo /home/goshil/.cargo/bin/trueno-ublk create --size 4G --algorithm zstd1 --high-perf
[TRACE] Device flags=0xC0, use_ioctl_encode=true
[TRACE] submit_fetch: tag=0, fd=6, cmd_op=0xC0107520, ioctl_encode=true
<....>
[TRACE] submit_fetch: tag=255, fd=6, cmd_op=0xC0107520, ioctl_encode=true
[TRACE]   pushed to submission queue OK
/dev/ublkb0

Seems like must be type swap here🤔?

sudo file -s /dev/ublkb0
/dev/ublkb0: data

Here is empty:

sudo /home/goshil/.cargo/bin/trueno-ublk list
        NAME     DISKSIZE         DATA        COMPR    ALGORITHM      STREAMS 

Device is persist

sudo /home/goshil/.cargo/bin/trueno-ublk find
/dev/ublkb0

sudo mkswap /dev/ublkb0  
Setting up swapspace version 1, size = 4 GiB (4294963200 bytes)
no label, UUID=e1e1d487-68e6-46af-bd2a-9e06e4ca8bd5

sudo swapon -p 150 /dev/ublkb0
swapon: /dev/ublkb0: read swap header failed

even tried this:

sudo dd if=/dev/zero of=/dev/ublkb0 bs=4096 count=256 
256+0 records in
256+0 records out
1048576 bytes (1,0 MB, 1,0 MiB) copied, 0,0025218 s, 416 MB/s

But still:

sudo swapon -p 150 /dev/ublkb0
swapon: /dev/ublkb0: read swap header failed

[noahgift]

Triage (2026-03-31): User-reported bug. Device created but not usable. Keeping open.

[noahgift]

Triage: P1 — runtime bug. Device ublkb0 created but not seen by trueno and swap subsystem. This blocks the core ublk use case. Needs investigation of device registration and udev rules.